There are hundreds of sedum varieties, but only a few, especially the shallow-rooting varieties, are suitable for a green roof. They can withstand heat, moisture, snow and are therefore almost indestructible, while other plants do not survive on a roof. One of the largest sedum nurseries in the Utrecht region is located in Odijk. On large fields in the vicinity of Odijk, Werkhoven, Bunnik and Cothen you can see Sempergreen’s 13 different types of sedum being grown. This takes an average of 9 to 12 months. In total, the company has 180 hectares of cultivation fields in the Netherlands. Nurseries are also established in Australia, Spain, Poland and Colombia. A new development is that sloping roofs can also become green, such as at the De Grote Geer family home in Houten.
More and more people want a green roof, but how green is that? ‘The cheapest sedum mat does not do much for biodiversity’
